Commutator



T. C. RUSSELL.

COMMUTATOR.

APPLICATION FILED MAR. 4. 1922.

1,432,038. Patnted Oct. 17, 1922-.

Patent ed Oct. 17, 1922.

UNITED srArss 'rnomis c. nussnnn, or cnrcaco, rumors.

commgraron.

7 Application filed umifl, 1922'. Serial 1%. 541,034.

To all whom it'may concern: i

Be it known that I, THoMAs C. RUssELL, a citizen of the United States, and a resident of Chicago,'in the county of Cook and State 'of Illinois, have invented certain new anduseful Improvements in Commutators, of-

which the'followin is a specification.

My invention re ates tocommutators for electric machines and in general the ob ect of the invention is to provide an improvedstructureand an improved process for makin such structure.

ore in detail one object of the invention is to produce a commutator-structure posis sessing great strength and rigidity and in which the commutator segments or bars are uniformly and efliciently insulated from each other. Another object is to provide an improved process for makin the commutator which will greatly simp ify and reduce the cost of manufacture, and insure rigid support for the commutator segments and unlform insulation thereof. I In accordance with my invention '1 first form a frame of the metal of which the se ments are to be composed, as for exampe copper, the segments forming an inte al part of the frame and being shaped an -located just as they will be in the finished commutator and separated for the reception between them of insulating material. The segments are primarily held together at one end by a section of the frame and while thus held insulating material, as for example bakelite, is moulded" to the frame and beinsulating material and properly insulated from each other thereby. The metal frame may be in the form of an ordinary casting or a die casting, or it maybe formed up from a sheet metal disk which is first cut or stamped to form radially extending and separated arms which form the commutator segments and their connectin flanges. The insulating material is applie to .this frame and between the segment members, a steel I bushing being preferably first inserted concentrically in the frame by means of which the finished structure may be mounted on a shaft. v

My improved commutator structure and '56 its manufacture are illustrated on the accompanying drawing, in which- Fig.1 is an end view of the commutator structure with part of the insulation removed to better show the shape of the segments,

Fig. 2 is a plan view of a sheet metal disk from which the commutator frame of Fig.

' 1 is formed up,

Fig. 3 is a diametral sectional view of the commutator,

Fig. 4 is a diametral sectional view showing a modified arrangement,

F 5 is a front elevational view of a radia type commutator Fig. 6 is an-end view of the commutator shown in Fig. 5, and

Fig. 7 is a sectional view on plane 7-7 Fig. 5.

The commutator shown in Fig. 1 is of the cylinder type comprising the commutator segments 10 with their connecting flanges 11 extendmg at right angles therefrom and the supporting core 12 of suitable insulating material, the axial cylindrical opening 13 being provided for mounting the commutator on a shaft, a metal bushin preferably provided in the opemng.

In accordance with my invention I first make a frame of copper or other suitable material, the segments properly shaped and suitably separated for insulation purposes forming integral parts of this frame and being primarily held in proper spaced relation by a section of the frame. Insulating material such as bakelite is then moulded to the frame and into the spaces between the segments whereafter that part of the frame which primarily holds the segments in spaced relation is cut away so that the bars will then be held solely by the insulating material and properly insulated from each other.

In Figs. 2 and 3 a simple arrangement is shown for forming a cylinder type commutator. As shown in Fig. 2 a circular disk of copper is cut radially by dies or otherwise to form the arms 15 which eventually become the commutator segments. At the center of the disk the hole 16 is formed for receiving the commutator shaft, and between the hole and the arms is the solid "section 17. The disk thus formed is subjected to a die operation which bends it at the lines 18 and 19 (Fig. 2) to produce the frame shown in Fig. 3. The frame comprises the head formed by the solid section 17 of the disk, the cylindrical part or brush 14 being receiving part formed b the commutator segments 10, and the ange' ends 11 to which the armature Wires or other conductors are to be secured. After formation of the frame the segments 10 and the flanges 11 will be uniformly spaced from each other by the insulating spaces 20.

After formation of the frame it is placed in a mould and insulating material 12 such as bakelite is poured in to form a supporting core, the insulating material entering the spaces 20 between the segments 10 and the flanges 11. Preferably a metallic bushing 14 is inserted centrally in the frame and through the hole 16 thereof before the insulating material is poured in, this bushing serving to mount the commutator on a shaft. After the insulating material has become properly set and hardenedthe solid art or head 17 of the frame is cut awaya ong the plane 00 Fig. 3 and then the insulated sections are no longer metallically connected but are uniformly insulated from each other by the insulating material.

Afvariety of ways may be resorted to for rigidly holding the segments to the lnsulating core. As shown in Fig. 1 the segments may be made wider at their inner sides so that the insulating material may have dovetailengagement therewith. Notches 23 may also be cut in the sides of the flanges 11 into which the insulating material engages to assist in looking the segments in place.

In Fi 4 a modified arrangement is shown for hol ing the segments in place, During formation of the metal frame the arms 15 are given notches 24 near their inner bends, and at their outer bends the metal is displaced inwardly to form retaining hooks or points 25. After moulding in of the insulating material the frame is then out along the line y and the section 17 is removed, the inner ends of the segment then presenting the retaining hooks or points 26. These hooks or points and the points 25 are received by and anchored in the insulating material and the segments are thus rigid- 1y held in place on the insulating core.

After the commutator structure is formed its cylindrical section is turned in a lathe or otherwise finished so that the commutator segments will present a smooth cylindrical surface for brushes.

In Figs. 5, 6, and 7 my invention is shown applied to the radial type of commutator.

A circular disk of cop er or other suitable material is slotted radially as shown at 27 to form the insulating spaces between the commutator segments 28. At the center of the disk is the hole 29 between which the commutator segments is the solid section 30 which primarily supportsthe segments in properly spaced osition. The disk is then placed in a mou d and insulating material such as bakelite applied thereto, a bushing 31 being preferably first inserted in the hole I 29. As shown a cylindrical backing or supof the segments into which the insulating material engages for dovetail interlocking connection with the segments to securely hold them in place.

I thus produce a very simple and efficient commutator structure which can readily and accuratel' be manufactured with little expense. he insulating material which forms the supporting core of the structure also engages between the commutator segments to insulate them from each other and to hold them in place. It is understood that changes and modifications can be made which will stillfall'within the scope of the invention.

Having described my invention, I claim as follows:

1.- The method of constructing a commutator which consists in slottin a metal disk to form radial arms but leavlng the center circular section of the disk unslotted, then deflecting the arms into parallelism with the disk axis to form and position the commutator segments, then applying insulating material to form a supporting core and to extend between the segments, and then cutting away the central unslotted part of the disk to leave the segments entirely insulated from each other and supported sole ly by the insulating material.

2. The method of constructing a commutator which consists in cutting a flat metal disk to provide radial arms but leaving the center circular section of the disk unslotted, then deflecting the arms into position to form .spaced apart commutator segments,

then applying plastic insulating material to form a supporting core and to extend between the segments, andthen cutting away the center part of the disk after setting of the insulatin material to leave the segments entirely insu ated from each other and supported solely by the insulating material.

3. A metal frame for commutator structures comprising a circular disk part, arms forming an inte a1 part of said disk and extending there rom and spaced apart to form commutator segments, and terminal flanges at the free end of said segments.

4. The method of construction a commutator which consists in stamping out a metal disk to leave the commutator segments and to leave the center section of the disk to primarily support the segments at one end, then moulding insulating material against and between t e segments to form a supportmg core therefor and then cutting away the and also to leave the center section of the disk to primarily support the segments at 15 one end, then mouldi insulating material against and between t e segments to form a supportin core therefor, and then cutting away t e center section of the disk to leave the segments entirely insulated from 20 each other and solely supported by said core.

In witness whereof, I hereunto subscribe my name this 1st day of March, D. 1922.

THOMAS C. RUSSELL 

